Vagus Nerve Stimulation in Crohn's Disease

Inclusion Criteria: * Male or female subjects aged 18-75 years, inclusive * Written informed consent prior to any of the screening procedures * Diagnosis of Crohn's disease for more than 4 months prior to Week -4 Visit, with small bowel and/or colonic involvement * Current evidence of moderately-to-severely active disease defined by a Week -4 Visit Crohn's Disease Activity Index (CDAI) score of 220 to 450, inclusive * Simple Endoscopic Score for Crohn's Disease evaluation at baseline showing presence of a minimal ulcer score of 2 or 3 in at least 1 segment * Levels of fecal calprotectin greater than or equal to 200 microgram/gram feces at Week -4 Visit * History of inadequate response and/or intolerance or adverse events leading to discontinuation of one or more TNF-alpha inhibitors (e.g., infliximab, adalimumab, or certolizumab pegol), or vedolizumab * Female subjects of child-bearing potential are eligible if not pregnant, not planning to become pregnant during the course of the study, and committed to use of contraceptive methods with a failure rate of less than 1 percent per year Exclusion Criteria: * Celiac disease * Diagnosis of ulcerative or indeterminate colitis * Enterocutaneous, abdominal or pelvic fistulae with abscesses, or fistulae likely to require surgery during the course of the study period * Bowel surgery, other than appendectomy, within 12 weeks prior to Week -4 Visit and/or has planned surgery or deemed likely to need surgery for Crohn's disease during the study period * Extensive colonic resection, subtotal or total colectomy * Presence of ileostomies, colostomies or rectal pouches * Fixed symptomatic stenoses of small bowel or colon * History of more than 3 small bowel resections or diagnosis of short bowel syndrome * Use of prohibited medications inside the specified washout period (prior to Week -4 Visit), and throughout the study. Prohibited medications include the following: * TNF antagonists and vedolizumab may continue throughout the study, but treatments should have been given at a stable dose for at least 6 months prior to the screening date and should be maintained at this level throughout the study * Use of any natalizumab within 8 weeks * Use of glucocorticoids at doses greater than 10 mg prednisone orally QD, or an equivalent dose of other oral or parenteral glucocorticoids within 4 weeks * Use of cyclosporine, tacrolimus, sirolimus or mycophenolate mofetil within 4 weeks * Use of intravenous antibiotics for Crohn's disease within 4 weeks * Use of tube or enteral feeding, or elemental diet within 2 weeks * Rectal Treatment: Use of 5-aminosalicylates or corticosteroid enemas or suppositories within 2 weeks * Azathioprine, 6-mercaptopurine and methotrexate can be continued throughout the trial. These medications must have been used for \>12 weeks, at stable dose for at least 3 weeks prior to the Week -4 Visit. * Leukocytopheresis or granulocytopheresis within 2 weeks prior to Week -4 Visit * Positive immunoassay for Clostridium difficile at Week -4 Visit * Known HIV infection * Known active in infection with Hepatitis B Virus or Hepatitis C Virus * Current evidence of, or has been treated for a malignancy within the past five years (other than localized basal cell or squamous cell skin cancer, cervical dysplasia, or any cancer which has been fully staged as in situ and has been fully resected) * History of evidence of adenomatous colonic polyps that have not been removed. * Use of any investigational product within 30 days prior to Week -4 Visit for small molecules, or 8 weeks prior for monoclonal antibodies * Significant psychiatric disease or substance abuse * History of unilateral or bilateral vagotomy * History of recurrent vaso-vagal syncope episodes * Known obstructive sleep apnea * Known history of cardiac rhythm disturbances, atrio-ventricular block of greater than first degree, or cardiac conduction pathway abnormalities other than isolated right bundle branch block or isolated left anterior fascicle block * Significant pharyngeal dysfunction or swallowing difficulties * Pre-existing clinically significant vocal cord damage or hoarseness * Previously implanted electrically active medical devices (e.g., cardiac pacemakers, automatic implantable cardioverter-defibrillators) * Asthma or chronic obstructive pulmonary disease not controlled by medications, or any other disease causing clinically significant dyspnea at time of screening * A greater than or equal to 40 pack-year smoking history * Active peptic ulcer disease